This invention relates to a diaphragm and connector assembly for vacuum-actuated automobile control systems. Door lock systems for automatically locking and unlocking the doors are a common example of such a control system featured in many automobiles.
In both of two known automobile control systems, a vacuum tank provides suction in either one of two output tubes. An electrical switch which is accessible to the occupant of the automobile controls a valve on the vacuum tank. Pushing the switch in one direction causes the vacuum tank to remove air through one of the tubes and pushing the switch in the other direction causes the valve to expose the first tube to the atmosphere and depressurize the second tube. The tubes are connected to a diaphragm actuator which in turn is linked to the automobile control such as a door lock mechanism. The air lines and the link between the diaphragm actuator in the automobile control system are setup such that when air is pumped from the first tube, the automobile control such as a door lock, is urged into one position by the diaphragm actuator. When the air pump removes air from the second tube, the diaphragm actuator urges the door lock toward another position.
The main difference between the two different control systems resides in the diaphragm actuators used. One type of diaphragm actuator uses a single pair of diaphragm elements while the other type uses a double pair of diaphragm elements. In the single pair diaphragm actuator, two diaphragms are disposed on opposing sides of a plastic form. The diaphragms are selectively depressurized, depending upon the position of the valve switch. A U-shaped bracket is attached to the closed end of each of the diaphragms. One end of the bracket is also attached to a linkage element which is, in turn, attached to the control system. A metal connector is seated within the closed, molded end of the diaphragm. The connector has a housing with an inner recess for holding a nut. The nut is kept from turning by the contoured walls of the housing. The top of the housing has an opening to permit access to the nut within the recess of the housing. The end of the U-shaped bracket has an aperture which is registered with the aperture in the connector housing. The linkage element is a threaded rod which is then extended through the apertures in the U-shaped bracket and connector housing into the nut. In this way, the linkage element is connected to the diaphragms through the metal connector and U-shaped bracket. Depressurizing of the diaphragms will, therefore, cause the U-shaped bracket to move up and down, thereby moving the connector and linkage rod with it and thereby, in turn, for example, locking or unlocking the door of a door lock mechanism.
Another type of diaphragm actuator operates in a very similar manner except that it uses two pairs of diaphragms instead of one. Each diaphragm pair is disposed in side by side relation on opposite sides of a plastic form. Each pair of diaphragms is selectively depressurized to move the door lock through a linkage element. Each of the four diaphragms has a metal connector seated within the closed end of the diaphragm. The door lock is connected to a rod which is, in turn, connected to a bracket assembly having two pair of bifurcated brackets. Each metal connector has a recessed neck portion for receiving one of the wings of the bracket assembly. Thus, as the diaphragms are depressurized, the connectors and bracket move up and down, which, in turn, moves the rod that operates the lock.
Occasionally, the rubber material of a diaphragm will become brittle and crack. Presently, if the owner of a car equipped with either of these types of diaphragm actuators finds that the diaphragms need to be replaced, his only recourse is to purchase an entire diaphragm actuator. No separate diaphragms or connectors are available. Additionally, even if separate diaphragms were available the diaphragm usable with the single pair actuator is not compatible with that used for the double pair actuator due to the difference in the connector structure.
There is, therefore, a need for a connector/diaphragm assembly which will operate interchangeably in either the single or double diaphragm actuator configuration.